Your biggest waste of time

[plucap]

Something that bothers me beyond most things are when you afterwards realize that something you've done is a complete waste of time. Something inside me hates that the most valuable resource of my life has gone to waste. Yeah I know it sounds corny and a little dramatic, but nevertheless I think it happens to most people

So what would you say is the biggest waste of time of your life?
(And before anyone else does it I'm gonna ensure myself by saying "reading this thread")